Transmission risk of asymptomatic SARS-CoV-2 infection: A systematic review and meta-analysis

Background Global evidence on the transmission of asymptomatic SARS-CoV-2 infection needs to be synthesized. Methods A search of 4 electronic databases (PubMed, EMBASE, Cochrane Library, and Web of Science databases) as of January 24, 2021 was performed. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Studies which reported the transmission rate among close contacts with asymptomatic SARS-CoV-2 cases were included, and transmission activities occurred were considered. The transmission rates were pooled by zero-inflated beta distribution. The risk ratios (RRs) were calculated using random-effects models. Results Of 4923 records retrieved and reviewed, 15 studies including 3917 close contacts with asymptomatic indexes were eligible. The pooled transmission rates were 1.79 per 100 person-days (or 1.79%, 95% confidence interval [CI] 0.41%–3.16%) by asymptomatic index, which is significantly lower than by presymptomatic (5.02%, 95% CI 2.37%–7.66%;P<.001), and by symptomatic (5.27%, 95% CI 2.40%–8.15%;P<.001). Subgroup analyses showed that the household transmission rate of asymptomatic index was (4.22%, 95% CI 0.91%–7.52%), four times significantly higher than non-household transmission (1.03%, 95% CI 0.73%–1.33%;P=.03), and the asymptomatic transmission rate in China (1.82%, 95% CI 0.11%–3.53%) was lower than in other countries (2.22%, 95% CI 0.67%–3.77%;P=.01). Conclusions People with asymptomatic SARS-CoV-2 infection are at risk of transmitting the virus to their close contacts, particularly in household settings. The transmission potential of asymptomatic infection is lower than symptomatic and presymptomatic infections. This meta-analysis provides evidence for predicting the epidemic trend and promulgating vaccination and other control measures. Trial Registration Registered with PROSPERO International Prospective Register of Systematic Reviews, CRD42021269446;https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=269446

Health disparities and COVID-19: A retrospective study examining individual and community factors causing disproportionate COVID-19 outcomes in Cook County, Illinois.

Early data from the COVID-19 pandemic suggests that the disease has had a disproportionate impact on communities of color with higher infection and mortality rates within those communities. This study used demographic data from the 2018 US census estimates, mortality data from the Cook County Medical Examiner's office, and testing results from the Illinois Department of Public Health to perform bivariate and multivariate regression analyses to explore the role race plays in COVID-19 outcomes at the individual and community levels. We used the ZCTA Social Deprivation Index (SDI), a measure of ZCTA area level deprivation based on seven demographic characteristics to quantify the socio-economic variation in health outcomes and levels of disadvantage across ZCTAs. Principal findings showed that: 1) while Black individuals make up 22% of Cook County's population, they account for 28% of the county's COVID-19 related deaths; 2) the average age of death from COVID-19 is seven years younger for Non-White compared with White decedents; 3) residents of Minority ZCTA areas were 1.02 times as likely to test positive for COVID-19, (Incidence Rate Ratio (IRR) 1.02, [95% CI 0.95, 1.10]); 1.77 times as likely to die (IRR 1.77, [95% CI 1.17, 2.66]); and were 1.15 times as likely to be tested (IRR 1.15, [95% CI 0.99, 1.33]). There are notable differences in COVID-19 related outcomes between racial and ethnic groups at individual and community levels. This study illustrates the health disparities and underlying systemic inequalities experienced by communities of color.

Health Disparities and COVID-19: A Retrospective Study Examining Individual and Community Factors Causing Disproportionate COVID-19 Outcomes in Cook County, Illinois, March 16-May 31, 2020 (preprint)

Background: Early data from the COVID-19 pandemic suggests that the disease has had a disproportionate impact on communities of color causing higher infection and mortality rates within those communities. Methods: This study used demographic data from the 2018 US census estimates, mortality data from the Cook County Medical Examiners office, and testing results from the Illinois Department of Public Health to perform both bivariate and multivariate regression analyses to explore the role race plays in COVID-19 outcomes at the individual and community levels. Results: Principal findings show that: 1) while Black Americans make up 22% of Cook County population, they account for 36% of the county COVID-19 related deaths; 2) the average age of death from COVID-19 is seven years younger for minorities compared to Non-Hispanic White (White) decedents; 3) minorities were more likely than Whites to have seven of the top 10 co-morbidities at death; 4) residents of predominantly minority areas were twice as likely to test positive for COVID-19 (p = 0.0001, IRR 1.94, 95% CI 1.50, 2.50) than residents of predominantly White areas; and 5) residents of predominantly minority areas were 1.43 times more likely to die of COVID-19 than those in predominantly White areas (p = 0.03). Conclusions: There are notable differences in COVID-19 related outcomes between racial and ethnic groups at individual and community levels. We hope that this study will scientifically illustrate the health disparities experienced by communities of color and help to address the underlying systemic inequalities still prevalent within our country.